Malvaceae TaxonomyHibiscus malvaceae

• Malvaceae Taxonomy •

Taxonomy (from the Greek τάξις, [taxis], for order, arrangement) is the branch of science concerned with the classification of organisms, systematically arranging them in a defined order. For additional information on this topic, see Botanical Latin.

The Malvaceae family presents many challenges for taxonomists. Opinions often differ as where to draw the lines between species, between genera, between tribes and between the subfamilies. This is not surprising —the Malvaceae family encompasses over 200 genera with close to 2,300 species! In terms of number of species, the largest genera include Hibiscus (~300 species), Sterculia (~250 species), Dombeya (~225 species), Pavonia (~200 species) and Sida (~200 species).

In recent years an expanded circumscription of the Malvaceae family has been created, which is composed of nine subfamilies. The relationships between these subfamilies are still obscure, and the subject of ongoing discussion. The traditional Malvaceae have been moved to Malvoideae, the subfamily that now approximately corresponds to that group.

The Nine Subfamilies of Malvaceae

Bombacoideae: (formerly Bombacaceae, in part), 12 genera, (~120 species).

Brownlowioideae: 8 genera, (~70 species).

Byttnerioideae: 26 genera, (~650 species).

Dombeyoideae: About 20 genera, (~380 species).

Grewioideae: 25 genera, (~770 species).

Helicteroideae: 8 to 12 genera, 10 to 90 species.

Sterculioideae: (formerly Sterculiaceae, in part), 12 genera, (~430 species).

Tilioideae: (formerly Tiliaceae, in part) 3 genera, (~50 species).

Malvoideae: (formerly Malvaceae), 78 genera, (~1,600 species). Temperate to tropical distribution. Subfamily Malvoideae now comprises the traditional Malvaceae and has consistently emerged as a very homogeneous, monophyletic group. In a recent treatment of Malvoideae, Bayer and Kutbitzki (2003) divide the subfamily into four tribes: Gossypieae, Hibisceae, Kydieae, and Malveae. The Malvoideae can be further ranked into the tribes listed below:

Malvoideae Tribes

Thursday, October 1, 2009

Tribe Gossypieae

Tribe Gossypieae has been redifined to include eight genera: Gossypium, Cephalohibiscus, Cienfuegosia, Hampea, Kokia, Gossypioides, Lebronnecia and Thespesia. It is specifically separated from the Hibisceae tribe based on embryo structure and the presence of pigment glands. These glands are associated with the capacity to synthesize the pigment gossypol. The Gossypieae appear to be unique in possessing these glands and this capacity.

More than 50 species of Gossypium are distributed in arid to semi-arid regions of the tropics and subtropics. Of these, four species were independently domesticated for their fiber (cotton) in Africa, Asia and the Americas. Gossypium species exhibit extraordinary morphological variation, with a diverse array of characteristics, ranging from trailing herbaceous perennials to 15m tall trees.

Tuesday, September 1, 2009

Tribe Hibisceae

Tribe Hibisceae is best known for its largest genus, Hibiscus —one of the world's most popular horticultural plant genera —which includes more than 300 species worldwide. The tribe Hibisceae includes (but is not limited to): Abelmoschus, Hibiscadelphus, Hibiscus, Kosteletzkya, Malvaviscus, Pavonia, Radyera, Talipariti and Wercklea.

Saturday, August 1, 2009

Tribe Kydieae

The Malvaceae family offers many challenges to taxonomists. Opinions often differ as where to draw the line between species, between genera, and between tribes. In the most recent treatment of Malvoideae (formerly Malvaceae), Bayer and Kutbitzki (2003) divide the subfamily into four tribes: Gossypieae, Hibisceae, Kydieae, and Malveae.

Wednesday, July 1, 2009

Tribe Malveae

Tribe Malveae includes approximately 70 genera (1000 species) that encompass the majority of the morphological and taxonomic diversity in the Malvoideae subfamily (Fryxell, 1997). The genera of Malveae exhibit a broad geographic distribution, with representatives in both tropic and temperate areas in a variety of habitats. Around 15 of the 70 Malveae genera have mostly temperate distributions, while some of the largest genera in the tribe (Abutilon, Sida, Nototriche) have primarily tropical distributions.

Malvaceae Taxonomy

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